PSG College of Technology

About: PSG College of Technology is a based out in . It is known for research contribution in the topics: Machining & Thin film. The organization has 3174 authors who have published 3575 publications receiving 40690 citations.

Wavelet based fault detection in analog VLSI circuits using neural networks

Abstract: This paper deals with a new method of testing analog VLSI circuits, using wavelet transform for analog circuit response analysis and artificial neural networks (ANN) for fault detection. Pseudo-random patterns generated by Linear Feedback Shift Register (LFSR) are used as input test patterns. The wavelet coefficients obtained for the fault-free and faulty cases of the circuits under test (CUT) are used to train the neural network. Two different architectures, back propagation and probabilistic neural networks are trained with the test data. To minimize the neural network architecture, normalization and principal component analysis are done on the input data before it is applied to the neural network. The proposed method is validated with two IEEE benchmark circuits, namely, the operational amplifier and state variable filter.

Rapid and high yield biogas production from Jatropha seed cake by co-digestion with bagasse and addition of Fe2+

Abstract: Co-digestion and metal ion addition strategies to improve the biogas production potential of Jatropha seed cake (JSC) by anaerobic digestion were evaluated in the present study. Initially, batch experiments were carried out to obtain the maximum JSC concentration for optimum biogas yield, followed by co-digestion with bagasse, and addition of Fe2+. The optimum JSC concentration of 15% (w/v) gave biogas production rate (BPR) of 66.4 mL/d, specific BPR of 9.7 mL/d/gVS and biogas yield of 0.064 m3/kgVS. The co-digestion strategy increased the carbon/nitrogen of feed (10% JSC+5% Bagasse, w/v) to 26.5 from 14 (JSC alone), resulting in biogas yield of 0.136 m3/kgVS of JSC, a 2.1-fold increase. Addition of Fe2+ to JSC and bagasse mixture led to biogas yield of 0.203 m3/kgVS, with methane content of 66% and methane production of 8.8 L/L reactor. With short digestion time of 15 days, co-digestion of JSC with bagasse and addition of Fe2+ showed 3.2-fold higher biogas yield than JSC alone.

Image Segmentation Using Artificial Neural Network and Genetic Algorithm: A Comparative Analysis

Abstract: Image segmentation is an important step in image processing. Most of the segmentation methods are parametric and the results of segmentation depend on the correctness of the estimated parameters. In case of supervised segmentation, a priori knowledge is needed for successful segmentation. So, nonparametric and unsupervised segmentation method is used when a priori information is not available. Kohonen's Self Organizing Maps (SOM), an unsupervised and nonparametric artificial neural network method is used to identify the main features present in the image. Genetic Algorithm (GA) can be applied to the results of SOM for optimal segmentation results. In this paper, the basic SOM, SOM combined with GA and some of the variants of SOM like the Variable Structure SOM (VSSOM), Parameterless SOM (PLSOM) are compared and their performance is evaluated. A new unsupervised, nonparametric method is developed by combining the advantages of VSSOM and PLSOM. The experiments performed on the satellite image shows that the modified PLSOM is efficient and the time taken for the segmentation is less when compared to the other methods.

Thermal annealing induced physical properties of ZnSe thin films for buffer layer in solar cells

Abstract: This article is dedicated to the study on the influence of thermal annealing on the physical properties of ZnSe thin films in order to seek a suitable alternative Cd-free window layer for developing high efficiency CdTe and CIGS solar cells. ZnSe films having thickness 300 nm were deposited onto glass and ITO substrates employing e-beam evaporation technique and then thermal annealing was undertaken in temperature range of 373–573 K with an interval of 100 K. The structural studies show that films are having cubic phase with (111) predominant peak and grain size corresponding to the preferred peak is observed to vary with annealing. The optical parameters like absorbance, transmittance, extinction coefficient, refractive index were also evaluated. The transmittance of films is found to vary and 573 K annealed films have shown maximum transmittance. The optical energy band gap was found to increase with annealing from 1.97 eV to 2.47 eV. Electrical analysis revealed the linear relationship between current and voltage indicating ohmic nature of the contacts. The results are also correlated with the surface morphology of the thin ZnSe films while the presence of Zn and Se peaks in EDAX spectra confirmed the film deposition.